In the webpage “The Concrete advantage” from the Green Rooftops’ website, the National Ready Mixed Concrete Association (NRMCA) explained why a concrete green rooftop is simple, inexpensive and durable compared to a membrane system. The concrete roofs are more feasible, which ensures better investment for the “society and owners”. It is also waterproof by nature, which eliminates the need for waterproofing sub-contractors. Both designing and detailing work are not needed too. This allows for a quicker construction and lower building cost. On top of that, it is highly probable that a root barrier is not required as well. The author also stated that the concrete green roofs do not deteriorate over time and they are easy to maintain. Unlike the membrane system, cracks are easily detected through leakages and fixing them only requires an injection.

While the article states the advantages of using a concrete green rooftop, it failed to state the drawbacks that come with a green rooftop.

First of all, there are requirements that a building structure has to fulfill before settling on a green roof. One of the factors is the thickness of the roofs. For the plants’ roots to grow properly, the thickness of the roofs must be 6-18inches thicker than a conventional roof. The added thickness will increase the weight of the roof and the load bearing walls of some buildings may not be able to support. On top of that, the roofs can only be built on a flat surface. “It should have no more than a 20-degree slope, if not lower, ideally as flat as possible” (Glazer, 2015). This makes the green roofs incompatible for some buildings.

The second drawback with a green roof is the cost. (NRMCA, 2011) stated that the green roofs are “financially viable, with less exposure risk for the owner and designer, which increases return on investment and project value.” The author further explained how having a green roof reduces the temperature in the building as it reflects the sun’s heat away than absorbing it. However, a white painted roof which is also known as a ‘cool’ roof, could produce similar results. (Strickland, 2009) stated that “Green roofs might cost $25 to $30 a square foot; a cool roof would cost a fraction of that”. The price of a green roof is almost twice the price of a conventional roof.

Last but not least, having a green roof requires much more maintenance than what the main webpage stated. A green roof is practically known as a garden on the roof and gardens require trimming from time to time.  On top of that, frequent inspections must be conducted to ensure that no leaks are present, ensuring the green roof is in good condition. In most cases, finding a leakage can be a complex task. It requires an electronic device that sends out electrical charges to trace the path of the leakage. If any leakages are found, repair works can be rather costly. All of these are the expenses to bear just to maintain a green roof.

In conclusion, I do not think that having a green roof is a good investment and the biggest advantage of having one, is the aesthetics. As nice as it looks, there are many unforeseeable circumstances and additional cost along the way. The advantages of the green roofs do not justify the price.


References

Salter, A. (2018, September 18). Disadvantages of Green Roofs.
Retrieved from https://www.hunker.com/12003790/disadvantages-of-green-roofs


Galbraith, K. (2009, May 19). Green Roofs: Are They Worth the Expense? Retrieved from https://green.blogs.nytimes.com/2009/05/19/green-roofs-are-they-worth-the-expense/


Downton, P. (2013, July 29). Green roofs and walls.
Retrieved from http://www.yourhome.gov.au/materials/green-roofs-and-walls


Taylor, M. (2015, May 22). What a Green Roof Costs You on the Way to Saving Everything.
Retrieved from https://www.thestreet.com/story/13161050/1/what-a-green-roof-costs-you-on-the-way-to-saving-everything.html

0 Comments